func expand<%= prefix -%><%= titlelize_property(property) -%>(v interface{}, d TerraformResourceData, config *Config) (interface{}, error) {
		if v == "" {
				return v, nil
		}
		val, err := parseZonalFieldValue("instances", v.(string), "project", "next_hop_instance_zone", d, config, true)
		if err != nil {
				return nil, err
		}

		userAgent, err := generateUserAgentString(d, config.userAgent)
		if err != nil {
			return nil, err
		}

		nextInstance, err := config.NewComputeClient(userAgent).Instances.Get(val.Project, val.Zone, val.Name).Do()
		if err != nil {
				return nil, err
		}
		return nextInstance.SelfLink, nil
}
